Adjustable bogey beam support for utility vehicles

ABSTRACT

A utility vehicle is provided with a bogey beam on which are mounted the steering axle at the forward end of the bogey beam and the middle axle on the rearward end of the bogey beam. A rear drive axle is supported by the frame of the utility vehicle. The bogey beam is connected to the frame by a pivot assembly defining a transverse pivot axis about which the bogey beam can oscillate. The weight transferred to the bogey beam is proportionately distributed between the front steering axle and middle axle. As a result, the steering characteristics of the steering axle are not impaired by the imposition of a load in the load bed of the utility vehicle, as the middle axle cannot be loaded sufficiently to overpower the front steering axle. The middle axle is rotatably driven by a chain drive transferring rotational power from the rear drive axle. The bogey beam is provided with a plurality of pivot axis locations to vary the proportions of the load applied to the front and middle axles as a result of the longitudinal movement of the bogey beam pivot.

FIELD OF THE INVENTION

[0001] The present invention relates generally to off-road motorvehicles, such as utility or recreational vehicles, and moreparticularly, to an adjustable bogey beam support apparatus for thefront and middle axles of a utility vehicle to vary the distribution ofload between the front and middle axles.

BACKGROUND OF THE INVENTION

[0002] Small off-road vehicles such as utility or recreational vehiclesare becoming popular for recreational and other general purpose off-roadusage. Such utility vehicles can be found in U.S. Pat. No. 4,706,770.These utility vehicles have found usage on golf courses and at sportingevents, and are particularly adaptable for utilization on a farm. Thistype of flexibility in the wide variety of uses necessitates a vehiclethat is highly flexible, highly maneuverable and the like. This demandsa vehicle that will afford a high degree of maneuverability and ease ofsteering.

[0003] Steering characteristics of known utility vehicles provide poorturning performance. Known utility vehicles have turning clearancecircles having a diameter greater than twenty-one feet. The use ofindependent front wheel suspension mechanisms on known utility vehicles,coupled with the mounting of the rack and pinion systems on the frame ofthe vehicle, introduces minor king pin rotations as the steering tiresride over ground undulations. Such construction reduces steeringprecision and can accelerate the wear of the tires on the steering axle.

[0004] Placing a load on the utility vehicle typically results in avariation in the steering performance of known utility vehicles. Forexample, one known embodiment having a front steering axle, a rear driveaxle, and a middle drive axle carries the load placed on the vehicle onthe middle and rear axles, resulting in proportionately less weight onthe steering axle and a reduction in maneuverability. Accordingly, knownutility vehicle construction results in a significant influence on thesteering performance by the load carried on the vehicle. Preferably,loads should not change the steering characteristics for any vehicle.

[0005] Furthermore, conventional utility vehicle construction mounts themiddle axle directly to the frame of the vehicle, resulting in a harshride characteristic and direct application of any load placed into theload bed onto the middle axle as well as the rear drive axle. It would,therefore, be desirable to enhance the ride characteristics, as well asthe steering performance of utility vehicles by distributing the weightof the loads being carried in a different manner.

[0006] Steering characteristics can be varied by changing the loadapplied to the front and middle axles. Depending on the steeringcharacteristics desired by the operator, it would be advantageous to beable to vary the proportional distribution of the load applied to thefront and middle axles.

[0007] It is therefor desirable to provide a utility and recreationalvehicle that overcomes the disadvantages of the known prior art utilityvehicles.

SUMMARY OF THE INVENTION

[0008] Accordingly, an important object of the present invention is toprovide a middle axle for a utility vehicle that is not directly mountedto the frame of the vehicle.

[0009] It is another object of this invention to provide a bogey beamapparatus for supporting the front and middle axles on a utilityvehicle.

[0010] It is a further object of this invention to provide support forthe middle axle of a utility vehicle in such a manner as to prevent theload placed thereon from overcoming the steering operation of the frontaxle.

[0011] It is a feature of this invention to add a bogey beam extendinglongitudinally at the center line of the utility vehicle to interconnectthe front and middle axles.

[0012] It is another feature of this invention that a portion of theload placed into the load bed of the utility vehicle will be distributedto the bogey beam to be re-distributed to the front and middle axles ina predetermined proportion.

[0013] It is still another object of this invention to provide anadjustable pivot mechanism for the bogey beam to vary the proportionalloading between the front and middle axles.

[0014] It is still another feature of this invention that theproportional loading between the front and middle axles can be varied atthe discretion of the operator.

[0015] It is an advantage of this invention that maneuverability of theutility vehicle is preserved during load bearing operations.

[0016] It is another advantage of this invention that the steeringcharacteristics of a utility vehicle can be adapted to the desires ofthe operator by changing the proportional loading between the front andmiddle axles.

[0017] It is still another advantage of this invention that the ridecharacteristics of a utility vehicle are improved, particularly underload bearing conditions.

[0018] It is still another feature of this invention that the loadsplaced on the load bed of the utility vehicle are proportionallydistributed between the front steering axle and the middle drive axle ofthe utility vehicle.

[0019] It is a further object of this invention to provide a bogey beammechanism for an off-road vehicle that is durable in construction,inexpensive to manufacture, carefree in maintenance, easy to assemble,and simple and effective in use.

[0020] These and other objects, features, and advantages areaccomplished according to the present invention by providing a utilityvehicle having a bogey beam on which are mounted the steering axle atthe forward end of the bogey beam and the middle axle on the rearwardend of the bogey beam. A rear drive axle is supported directly on orsuspended from the frame of the utility vehicle. The bogey beam can berigidly or resiliently connected to the frame by a pivot assemblydefining a transverse pivot axis about which the bogey beam canoscillate. The weight transferred to the bogey beam is proportionatelydistributed between the front steering axle and middle axle. As aresult, the steering characteristics of the steering axle are notimpaired by the imposition of a load in the load bed of the utilityvehicle, as the middle axle cannot be loaded sufficiently to overpowerthe front steering axle. The bogey beam is provided with a plurality ofpivot axis locations to vary the proportions of the load applied to thefront and middle axles as a result of the longitudinal movement of thebogey beam pivot.

[0021] The foregoing and other objects, features, and advantages of theinvention will appear more fully hereinafter from a consideration of thedetailed description that follows, in conjunction with the accompanyingsheets of drawings. It is to be expressly understood, however, that thedrawings are for illustrative purposes and are not to be construed asdefining the limits of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The advantages of this invention will be apparent uponconsideration of the following detailed disclosure of the invention,especially when taken in conjunction with the accompanying drawingswherein:

[0023]FIG. 1 is side perspective view of a utility vehicle incorporatingthe principles of the present invention;

[0024]FIG. 2 is a top plan view of the utility vehicle of FIG. 1, theseats and control apparatus being shown in dashed lines, the frame andaxles being shown in phantom;

[0025]FIG. 3 is a top plan view of the frame and drive mechanism withthe chassis removed for purposes of clarity;

[0026]FIG. 4 is an enlarged cross-sectional view of the utility vehicletaken along lines 4--4 of FIG. 3 to show the drive mechanism and theorientation of the bogey beam supporting the front steering axle and themiddle drive axle;

[0027]FIG. 5 is an enlarged cross-sectional view of the utility vehicletaken along lines 5--5 of FIG. 3 to show an elevational view of themiddle drive axle;

[0028]FIG. 6 is an enlarged cross-sectional view similar to that of FIG.4 but showing flotational movement of the middle axle, the normalposition of the middle axle being shown in phantom;

[0029]FIG. 7 is a top plan view of the frame similar to that of FIG. 3,but showing variable placement of the bogey beam pivot, alternativebogey beam pivot locations being shown in phantom; and

[0030]FIG. 8 is an enlarged cross sectional view similar to that of FIG.4, but showing variable placement of the bogey beam pivot, alternativebogey beam pivot locations being shown in phantom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Referring to FIGS. 1-3, a utility vehicle incorporating theprinciples of the present invention can best be seen. Any left and rightreferences are used as a matter of convenience and are determined bystanding at the rear of the vehicle and facing forwardly into thedirection of travel.

[0032] The utility vehicle 10 includes a frame 12 supported above theground G by a pair of steered wheels 22, 23 mounted on a front steeringaxle 20 and by a pair of driven wheels 25 mounted on a rear drive axle24. In the preferred embodiment depicted in FIGS. 1-3, a middle driveaxle 27 is also provided with a pair of opposing support wheels 28. Theframe 12 supports an operator compartment 13 including seats 14 for thecomfort of the operator and control apparatus, such as a conventionalsteering wheel 15 and a gear shift lever 16. A throttle control 17 and abrake control 18, along with other conventional control devices, arealso included within the operator compartment 13 for the control of thevehicle 10. The frame 12 also supports a load bed 19 rearwardly of theoperator compartment 13 over the middle and rear drive axles 27, 24respectively, to carry cargo over the surface of the ground G.

[0033] Referring now to FIG. 3, the frame 12 with the axles 20, 24, 27mounted thereon can best be seen. The rear drive axle 24 is rotatablysupported on the frame 12 and is powered by a drive mechanism 26 poweredby an engine 11 supported by the frame 12. The middle axle 27 ispivotally supported from the frame 12 by a pair of support links 29 andis connected to the rearward end of a bogey beam 30, which will bedescribed in greater detail below. The middle axle 27 is preferablyformed as a pair of stub shafts 27 a, 27 b connected to said respectivesupport links 29. A support beam 32 is pivotally mounted on a rearwardend of the bogey beam 30 for oscillatory movement about a longitudinallyextending pivot axis 33 a. The support wheels 28 on the middle axle 27are driven by respective chain drives 26 a to provide a four wheel drivecapability for the vehicle 10.

[0034] Front axle 20 and the mounting member 35 are attached to theforward end of the bogey beam 30 and, therefore, also pivot about axis33 a. The bogey beam 30 is pivotally connected to the frame 12 by apivot assembly 37 positioned beneath the operator compartment 13 toprovide an oscillation of the bogey beam 30 about the transverse pivotaxis 38. Accordingly, the front steering axle 20 and the middle axle 27generally oscillate in opposing vertical directions on opposite ends ofthe bogey beam 30 due to the pivotal mounting thereof by the pivotassembly 37.

[0035] The pivot assembly 37 can be formed as a simple pin pivotallyconnecting the bogey beam 30 to the frame 12 of the vehicle 10 to definethe transverse pivot axis 38, as is shown in the drawings. The pivotassembly 37 can also suspend the bogey beam 30 from the frame 12 byproviding a link (not shown) that pivotally connects at one end to thebogey beam 30 and is centrally connected to the frame 12 with theopposing end of the link being connected to a spring mechanism (notshown) that provides some resiliency between the bogey beam 30 and theframe 12. Under such a suspended bogey beam arrangement, the transversepivot axis 38 would be located at the pivotal connection between thelink (not shown) and the bogey beam 30, but would be vertically movablerelative to the frame 12 about the pivotal connection between the link(not shown) and the frame 12, the spring mechanism (not shown)interconnecting the frame 12 and the link (not shown) to offset forcesencountered by the bogey beam 30. The location of the central pivot onthe link (not shown), pivotally connecting the link to the frame 12,being positioned between the opposing ends of the link to provide thedesired resiliency for the selected size of the spring mechanism.

[0036] Any load placed in the load bed 19 will be transferred to therear axle 24 through the mounting thereof with the frame 12 and to thebogey beam 30 via the pivot assembly 37. The weight carried by the bogeybeam 30 will be shared in a proportionate manner between the frontsteering axle 20 and the middle axle 27. The respective proportions willbe determined by the location of the pivot assembly 37 along a length ofthe bogey beam 30. Accordingly, any load transferred to the bogey beam30 will always be proportionately divided between the front steeringaxle 20 and the middle axle 27. As a result, the steeringcharacteristics will not be impacted by any load placed into the loadbed 19, as the middle axle 27 cannot overpower the front steering axle20.

[0037] The front steering axle 20 is operatively associated with asteering mechanism 40 to effect turning movement of the steered wheels22, 23. The steering mechanism 40 is actuated through manipulation ofthe steering wheel 15 by the operator through the universal connectinglinkage 42. The steering mechanism 40 includes a rack and pinionassembly 45 which includes a conventional pinion (not shown) rotatablyassociated with the steering wheel 15 and a conventional rack 47 that islinearly movable in conjunction with the rotation of the pinion 46 in aknown manner.

[0038] The rack 47 is pivotally connected to a first bell crank 50 at afirst connection point 48. The first bell crank 50 is pivotally mountedon the mounting member 35 for movement about a pivot 51. The connectionpoint 48 is positioned forwardly of the pivot 51 to effect pivotalmovement of the first bell crank. The right steered wheel 22 includes aspuckle 52 having a steering arm 53 extending rearwardly therefrom. Thefirst bell crank 50 is connected to the right steering arm 53 by asteering link 54 that extends laterally and rearwardly from the firstbell crank 50 to the rearward end of the steering arm 53.

[0039] The steering mechanism 40 also includes a second bell crank 55pivotally mounted on the mounting member 35 for movement about a pivot56. The second bell crank 55 is connected to the first bell crank 50 bya tie rod 60 for coordinated movement therebetween. Accordingly, pivotalmovement of the first bell crank 50 is transferred to the second bellcrank 55 through connection with the tie rod 60. The left steered wheel23 includes a spuckle 57 having a steering arm 58 extending rearwardlytherefrom. The second bell crank 55 is connected to the left steeringarm 58 by a steering link 59 that extends laterally and rearwardly fromthe second bell crank 55 to the rearward end of the steering arm 58.Accordingly, the left and right steered wheels 22, 23 are steered inconcert with one another in response to a manipulation of the steeringwheel 15 by the operator.

[0040] Referring now to FIGS. 3-5, the details of the bogey beamconstruction and the support of the middle drive axle 27 can best beseen. The support beam 32 at the rear end of the bogey beam 30 has thestub axles 27 a, 27 b mounted directly to the laterally opposing ends ofthe support beam 32. The support beam 32 further has a pair of mountingbrackets 34 projecting rearwardly therefrom interiorly of the stubshafts 27 a, 27 b to pivotally connect with the support links 29. Thesupport links 29 pivotally interconnect the frame 12 just forwardly ofthe rear drive axle 24 and the mounting brackets 34 on the support beam32. While the drawings depict the support links 29 connected to theframe 12 and the rear drive axle 24 fixed to the frame 12, analternative configuration can suspend the rear drive axle 24 from theframe 12 such that the rear drive axle 24 is vertically movable relativeto the frame 12. In such a configuration, the support links 29 wouldpreferably be mounted to the rear drive axle 24 to be vertically movabletherewith, but pivotable about an axis that is not coincidental with theaxis of the rear drive axle 24. Furthermore, the pivotal connectionbetween the support links 29 and either the frame 12 or the rear driveaxle 24, or alternatively the length of support links 29, will bepositionally adjustable in a fore and aft direction to provide foradjustment of the tension in the chain drive mechanism 26 a, as will bedescribed in greater detail below.

[0041] The support beam 32 is also connected to a central supportbracket 31 which, in turn, is connected to the rearward end of the bogeybeam 30 by a ball joint 33 defining the oscillation axis 33 a whichpermits the middle axle 27 to oscillate about a longitudinally extendingaxis 33 a to permit the middle axle 27 to follow ground undulations. Thecentral support bracket 31 also defines a pivotal connection between thebogey beam 30 and the support beam 32 such that the support beam 32which is fixed to the central support bracket 31 is free to pivot abouta bolt defining a transversely extending pivot axis 31 a that iseccentric with respect to the transverse axis of the middle axle 27.Accordingly, the middle axle 27 is capable of simultaneous pivotalmovement about the transverse axis 31 a and the pivotal connectionsbetween the support links 29 and the mounting brackets 34. Preferably,the pivotal connection between the support links 29 and the mountingbrackets 34 are in alignment with the stub shafts 27 a, 27 b definingthe middle axle 27. The transverse pivot axis 31 a is located below theline of the middle axle 27.

[0042] The pivotal connection of the support links 29 to the frame 12(or alternatively to the rear drive axle 24) is preferably formed as anassembly that is longitudinally movable to control the tension in thechain drive mechanism 26 a. With specific reference to FIG. 4, theposition of the support beam 32 on top of the bogey beam depicts theforwardmost adjustable movement of the support links 29. One skilled inthe art will readily recognize that a fore-and-aft movement of thesupport link 29 will cause pivotal movement of the support beam 32 aboutthe transverse pivot axis 31 a carried by the rearward end of the bogeybeam 30. Accordingly, the normal operative position of the support beam32 will be at an orientation above the bogey beam 30 to allow for wearadjustment of the chain mechanism 26 a, similar to the solid linedepiction in FIG. 6.

[0043] In operation, as best seen in FIGS. 4-6, the middle axle 27 isfree to float with respect to frame 12 of the utility vehicle 10. Thevertical movement of the middle axle 27 is accommodated by the pivotalconnections of the support links 29, the bogey beam 30 and the supportbeam 32. The support links 29 impose a controlled positionalrelationship with respect to the movements of the middle axle 27relative to the rear drive axle 24, thus keeping the chain drivemechanism 26 a in a proper drive transferring condition. The supportlinks 29 do not pivot on a center coincident with the rear drive axle24, but are pivoted at a point forwardly of the rear drive axle 24.Accordingly, the pivotal movement of the middle axle 27, as representedby the arc 29 a, will slightly shorten the distance between the middleaxle 27 and the rear drive axle 24, thus allowing a little slack in thechain drive mechanism 26 a to accommodate a slight twisting of the chaindrive mechanism 26 a when the middle axle oscillates about the pivotaxis 33 a. The floating movement of the middle axle 27 about therearward end of the support links 29, whose pivot axis is forward of therear drive axle 24, will maintain acceptable tension in the chain drivemechanism 26 a for proper drive transmission to the middle axle 27.

[0044] Furthermore, the middle axle 27 is mounted on the rearward end ofthe bogey beam 30 and any vertical floating movement of the middle axle27 must also move in conjunction with the limits imposed by the bogeybeam structure 30, as represented by the arc 30 a. Since the supportbeam 32 is pivotally connected to the rear end of the bogey beam 30 bythe central support bracket 31, the support beam 32 is capable ofpivoting rearwardly about the pivot axis 31 a, as represented by the arc32 a. Accordingly, the middle axle 27 vertically floats through pivotarcs 29 a, 30 a, and 32 a that coordinate to provide substantiallyvertical movement for the middle axle 27.

[0045] The vertical floating movement of the middle axle 27 is bestshown in FIG. 6. The normal position of the middle axle 27 is shown inphantom lines, while the raised position of the middle axle 27 toaccommodate a ground undulation is shown in solid lines. The verticalmovement of the middle axle 27 raises the rearward end of the bogey beam30, pivoting the bogey beam 30 about the front axle 20, and slightlyraises the operator compartment 13 as represented by the verticalmovement of the transverse pivot 38. The pivotal movement of the middleaxle 27 with respect to the support links 29 results in a correspondingpivotal movement of the central support bracket 31 about pivot axis 31a, causing the support beam 32 to raise above the bogey beam 30. Thisflotational capability of the middle axle 27 results in a smoother ridefor the operator than is known in the prior art construction with themiddle axle 27 fixed to the frame 12.

[0046] The downward vertical movement of the middle axle 27 results in asimilar operation of the pivot arcs 29 a, 30 a, and 32 a. The downwarddisplacement of the middle axle 27 moves the rearward end of the bogeybeam 30 downwardly along the arc 30 a. The fixed length of the supportlinks 29 results in a pivotal movement of the support beam 32 about thetransverse pivot axis 31 a, raising the support beam 32 relative to thebogey beam 30.

[0047] An alternative configuration of the pivot assembly 37 can best beseen in FIGS. 7-8. By changing the location of the pivot axis 38, theproportions of the load distribution between the front and middle axles20, 27 can be varied due to the difference in moment arms between thefront and middle axles 20, 27 and the pivot axis 38. Changing the loaddistribution provides a difference in steering characteristics which canbe selected by the operator simply by relocating the pivot axis 38 intoone of the alternative openings 38 a, 38 b in the bogey beam 30.Alternatively, the pivot assembly 37 can be equipped with an automaticadjustment mechanism (not shown) that would effect a relocation of thepivot axis 38 by the operator from the operator compartment 13.

[0048] The invention of this application has been described above bothgenerically and with regard to specific embodiments. Although theinvention has been set forth in what is believed to be the preferredembodiments, a wide variety of alternatives known to those of skill inthe art can be selected within the generic disclosure. The invention isnot otherwise limited, except for the recitation of the claims set forthbelow.

Having thus described the invention, what is claimed is:
 1. In a utilityvehicle having a frame supported by a steering axle having a pair ofsteered wheels pivotally mounted thereon, a rear axle supported from theframe and having a pair of wheels mounted thereon, and a middle axlehaving a pair of support wheels mounted at opposing ends thereof, theimprovement comprising: a longitudinally extending bogey beam pivotallyconnected to the frame and having a forward end and a rearward end, saidsteering axle being connected to said forward end of said bogey beam andsaid middle axle being connected to said rearward end of said bogeybeam; a pivot assembly connecting said bogey beam to said frame, saidpivot assembly defining a transverse pivot axis about which said bogeybeam is pivotable, said pivot axis being selectively positionable alonga longitudinal length of said bogey beam.
 2. The utility vehicle ofclaim 1, wherein said pivot assembly is selectively mountable at one ofmultiple predetermined locations on said frame.
 3. The utility vehicleof claim 2, wherein said pivot axis can be moved along said longitudinallength of said bogey beam through manipulation of a control device at aremote location.
 4. The utility vehicle of claim 3, wherein the movementof said pivot axis along the longitudinal length of said bogey beamchanges the distribution of a load applied to said bogey beam betweensaid front and middle axles.
 5. The utility vehicle of claim 4, whereinthe movement of said pivot axis rearwardly toward said middle axleincreases the proportional load distribution on said middle axle.
 6. Theutility vehicle of claim 5, wherein said bogey beam is formed with aplurality of holes therein for positioning said pivot axis.
 7. A utilityvehicle comprising: a frame; a rear axle supported from the frame andhaving a pair of wheels mounted thereon; a steering axle having a pairof steered wheels pivotally mounted thereon; a middle axle having a pairof support wheels mounted at opposing ends thereof; a longitudinallyextending bogey beam having a longitudinal length extending between aforward end supporting said steering axle and a rearward end supportingsaid middle axle; and a pivot assembly connecting said bogey beam tosaid frame, said pivot assembly defining a transverse pivot axis aboutwhich said bogey beam is pivotable, said pivot assembly beingselectively mountable at one of multiple predetermined positions alongsaid longitudinal length of said bogey beam.
 8. The utility vehicle ofclaim 7, wherein said pivot axis can be moved along said longitudinallength of said bogey beam through manipulation of a control device at aremote location.
 9. The utility vehicle of claim 7, wherein the movementof said pivot axis along the longitudinal length of said bogey beamchanges the distribution of a load applied to said bogey beam betweensaid front and middle axles.
 10. The utility vehicle of claim 9, whereinthe movement of said pivot axis rearwardly toward said middle axleincreases the proportional load distribution on said middle axle. 11.The utility vehicle of claim 10, wherein said bogey beam is formed witha plurality of holes therein for positioning said pivot axis.
 12. In autility vehicle having a frame supported by a steering axle having apair of steered wheels pivotally mounted thereon, a rear axle supportedfrom the frame and having a pair of wheels mounted thereon, and a middleaxle having a pair of support wheels mounted at opposing ends thereof,the improvement comprising: a longitudinally extending bogey beampivotally connected to the frame and having a forward end and a rearwardend, said steering axle being connected to said forward end of saidbogey beam and said middle axle being connected to said rearward end ofsaid bogey beam; and said steering axle and said middle axle beingpivotally connected to said bogey beam such that each of said steeringaxle and said middle axle are independently movable relative to saidbogey beam about a longitudinally extending axis, thereby allowing eachof said steering axle and said middle axle to oscillate in a generallyvertical plane relative to said frame.
 13. The utility vehicle of claim12 wherein said middle axle is connected to said rearward end of saidbogey beam by a ball joint.
 14. The utility vehicle of claim 12 whereinsaid steering axle includes a mounting member pivotally connected tosaid forward end of said bogey beam for movement thereof about saidlongitudinally extending axis.
 15. The utility vehicle of claim 12wherein said bogey beam is pivotally connected to said frame by a pivotassembly defining a transverse pivot axis about which said bogey beam ispivotable, said pivot assembly being selectively mountable at one ofmultiple predetermined positions along said longitudinal length of saidbogey beam.
 16. The utility vehicle of claim 15, wherein the movement ofsaid pivot axis along the longitudinal length of said bogey beam changesthe distribution of a load applied to said bogey beam between said frontand middle axles.